1 . Field of the Invention
The present invention generally relates to a structural assembly in a vehicle. More specifically, the invention relates to an impact countermeasure assembly that responds to a frontal impact, such as a small overlap impact, to limit the frontal impact force on the vehicle cabin.
2 . Description of Related Art
Automotive vehicles are often constructed at their front ends to include various support structure for the engine, wheels, suspension, bumper, and related components. These support structures can include members that are generally aligned with the longitudinal axis of the vehicle, that run in a generally transverse direction relative to the longitudinal members or at oblique angles to these axes. The support structures surrounding and supporting the engine compartment are ultimately connected to various structures that define the vehicle cabin. These cabin support structures can include a generally vertical door hinge pillar, the A-pillar that extends from the door hinge pillar to the roof of the vehicle, a laterally extending cross beam, a floor pan running across the width of the vehicle, and a rocker member extending rearwardly from the bottom of the hinge pillar.
These support structures provide support for various vehicle components, as well as exterior structures, that are mounted thereto. Examples of vehicle components include the engine, transmission, radiator, suspension, wheels, and the like. Examples of exterior structures include the doors, roof, windshield, floor panels, hood, and the like. In addition to providing support for the various vehicle parts, the support structure also operates to protect the vehicle occupants in the event of a collision, such as a frontal impact collision.
One type of frontal impact collision is known as a small overlap impact. A small overlap impact is an impact where the majority of loading due to the impact occurs outside of the major longitudinal support structures of the vehicle. A small overlap impact can occur in a variety of ways, such as a head on collision with a tree or post, a vehicle to vehicle oblique collision, or a vehicle to vehicle collinear or head-on collision.
Because the majority of the loading is outside the longitudinal support structures, the impacting body or “barrier” can result in the longitudinal support structure slipping off the barrier. Put another way, the vehicle longitudinal support structures may deform laterally inward relative to the barrier or provide limited interaction with the barrier. The barrier could continue to exert a longitudinal force toward the vehicle, with the force generally aligned with the wheel of the vehicle due to the relative lateral translation. Upon impact with the wheel, the force may be transmitted further toward the rear of the vehicle and toward the passenger cabin. The barrier and wheel would then exert a force upon the hinge pillar, the rocker, the A-pillar, the floorpan, and cross beam, each of which are at least partially aligned with the barrier during this type of collision. These structures can ultimately deform due to the collision with the barrier, resulting in encroachment of the structures upon the passenger cabin.
One solution to these issues of cabin encroachment has been to reinforce the longitudinal support structure and the support structures that surround the cabin, so as to limit the deformation of these structures. However, the additional reinforcement can result in substantial increases in vehicle mass and material, which are undesirable in terms of cost and fuel mileage.